Before now, with the purpose of improving printing efficiency for image forming devices such as copiers, printers, or the like, a general usage was to print two pages on one sheet of printing paper, of the size of two document pages, and cut along the center line of the printed sheets. A method is known for forming binding holes or binding margins on the sheets, in the case where the printed sheets are cut along the center line of the sheets and stacked, after which binding processing is performed. In devices which do not perform binding processing, an image forming method is known which can stack the pages in ascending order if the printed sheets are stacked in cutting order.
However, these technologies relate to devices including binding processing and cannot be applied in many cases where binding processing is not necessary. When performing a print image forming method with the latter technique, the cutting edges of the cut sheets after printing are not the same because two document pages are combined and printed on the same side of one sheet, as shown in FIG. 2. Therefore, when the printed sheets are stacked, the sheets are not aligned and this situation is not convenient.
Also, with the former image forming method, because the position of the binding margins or binding holes of the printed sheets are different for each page as shown in FIG. 14, a problem is that when the sheets are cut and stacked, the print images are printed in a disordered manner on the fronts and backs of the sheets. In a prior art image forming method, a problem is that the binding margin is not positioned within the sheet, as shown in FIG. 15. When adding the positioning of the binding margin to printing with the latter technique, a problem is that the position of the binding margin varies from page to page because the cutting edge of the paper cut along the center line thereof appears on the right side or the left side (FIG. 16).
The present invention was developed in view of these issues and an object thereof is to provide an image forming device and image forming method which is convenient, and which prevents sheets from becoming unaligned and arranged in descending order by page number, when printed sheets are stacked after the sheets are printed and cut.
Also, the present invention was developed in view of these issues and an object thereof is to provide an image forming device and image forming method for printing sheets such that the binding margin is positioned at a specified binding margin position and such that the side where the binding margin is positioned is the cutting edge.